New microfluidic chip can help identify unwanted particles in water and food

Jun 19, 2013

Virginia Tech's Masoud Agah, associate professor of electrical and computer engineering, is a past recipient of a National Science Foundation CAREER Award for his work in three-dimensional micromachining and its use in microfluidics and chemical detection. Credit: Virginia Tech

A new process for making a three-dimensional microstructure that can be used in the analysis of cells could prove useful in counterterrorism measures and in water and food safety concerns.

The research, conducted by members of Virginia Tech's Microelectromechanical Systems Laboratory (MEMS) Laboratory in the Bradley Department of Electrical and Computer Engineering, is the focus of a recent article in the Institute of Electrical and Electronic Engineers' Journal of Microelectomechanical Systems.

In their engineering laboratory, the researchers developed a new microfabrication technique to develop three-dimensional microfluidic devices in polymers. Microfluidics deals with the performance, control, and treatment of fluids that are constrained in some fashion, explained Masoud Agah , director of the laboratory.

As a result of this work, Agah, associate professor of the Bradley Department of Electrical and Computer Engineering and of the Virginia Tech–Wake Forest School of Biomedical Engineering and Sciences, and Amy Pruden, professor of civil and environmental engineering at Virginia Tech, have received a National Science Foundation award of $353,091 to use the technology and develop new microchips named 3D-πDEP standing for "three-dimensional, passivated-electrode, insulator-based dielectrophoresis" for pathogen detection.

The NSF grant will allow them to focus on the isolation of waterborne pathogens that represent one of the "grand challenges to human health, costing the lives of about 2.5 million people worldwide each year," Agah and Pruden said.

According to the World Health Organization, the isolation of pathogenic bacteria from the environment has not significantly changed since the 1960s, when methods for chemical treatment of samples to remove background organisms were first implemented.

In the past, Agah said, researchers have mainly used two-dimensional microfluidic structures since this type of fabrication is more simplistic. With the three-dimensional device developed by Agah and his collaborators, Yayha Hosseini and Phillip Zellner, both graduate students in the department, they are able to customize the shapes of the channels and cavities of the devices the fluids passed through.

The advantage of the fabrication process is that with a very economical technique it creates three-dimensional varying channels and cavities in a microfluidic structure with rounded corners as well as many other customized shapes.

These shapes are important because they resemble the living conditions as they occur naturally and this allows the use of the three-dimensional microfabrication technology beyond pathogen detection.

As an example, in human blood vessels, cells interact with each other and their surrounding environment inside circular channels. They have varying diameters, along with multiple branching and joints.

"Only under this type of condition can one truly study the biology of cells within a system in vitro as if it is occurring in vivo – our new microfluidic fabrication technology can resemble more realistically the structures of a cell's true living conditions," Agah said. It is the introduction of the three-dimensions that provides this distinctive environment.

The combination of Agah and Pruden's expertise is important to the NSF-awarded work.

Pruden has a broad background in applied environmental microbiology, and has worked extensively in the detection and characterization of pathogens in various environmental systems. She is also leading other research efforts focused on the detection and monitoring of various pathogens and antibiotic resistant pathogens in drinking water and in wastewater.

Agah is the recipient of a National Science Foundation CAREER Award for his work in three-dimensional micromachining and its use in microfluidics and chemical detection.

Prudent also has a CAREER award as well as a presidential Early Career Award in Science and Engineering.

By blending their proficiencies, with Agah's group designing, modeling, and fabricating the chips, and Pruden's group preparing the different bacterial cultures for characterizing their dielectrophoresis properties and benchmarking it against more acceptable yet costly methods, they believe they will be able to isolate different pathogenic and nonpathogenic bacteria.

To make their three-dimensional structure, the Virginia Tech researchers used the material polydimethylsixolane, known for its elastic properties similar to rubber. This material is already widely used because of its transparency, biocompatibility, and low-cost.

"Our work establishes a reliable and robust, yet low-cost technique for the fabrication of versatile 3-D structures in polydimethylsixolane," Agad said.

Microfluidic devices can be used to trap and sort living organisms such as bacteria, viruses, and cells. With this new three-dimensional device that has a higher sensitivity and throughput than the two-dimensional version, according to Agah, he is able to make their predictions of applications ranging from water and food safety to fighting biological and chemical terrorism and to healthcare by fishing for abnormal cells in body fluids.

Both Hosseini of Kashan, Iran, and Zellner of Hampton, Va., are working on their doctoral degrees. Zellner is a SMART scholarship recipient from the Department of Defense.

Related Stories

Developing a credit-card-sized gas chromatography platform that can analyze volatile compounds within seconds is the next step for Virginia Tech College of Engineering researcher Masoud Agah, who has received a National Science ...

Using ovarian surface epithelial cells from mice, researchers from Virginia Tech have released findings from a study that they believe will help in cancer risk assessment, cancer diagnosis, and treatment efficiency ...

A bioengineering research team from the National University of Singapore (NUS) team led by Associate Professor Zhang Yong has developed a novel microfluidic device for efficient, rapid separation and detection ...

The field of 3-D printing technology is revolutionizing industries across the spectrum, from the arts to electronics. We asked Constantinos Mavroidis, Distinguished Professor of Engineering, to explain how ...

(Phys.org) —Researchers at the University of Illinois at Urbana-Champaign have developed a new flow-based method for manipulating and confining single particles in free solution, a process that will help ...

Recommended for you

(Phys.org)—As lithium resources continue to decline worldwide, the next generation of portable electronics will most likely be powered by something other than Li-ion batteries. One potential candidate is ...

Dislocations in oxides such as cerium dioxide, a solid electrolyte for fuel cells, turn out to have a property that is the opposite of what researchers had expected, according to a new analysis at MIT.

Cancer patients fear the possibility that one day their cells might start rendering many different chemotherapy regimens ineffective. This phenomenon, called multidrug resistance, leads to tumors that defy ...

A novel nucleating agent that builds on the concept of molecularly imprinted polymers (MIPs) could allow crystallographers access to proteins and other biological macromolecules that are usually reluctant ...

Researchers from institutions including Lund University have taken a step closer to producing solar fuel using artificial photosynthesis. In a new study, they have successfully tracked the electrons' rapid transit through ...

User comments : 0

Please sign in to add a comment.
Registration is free, and takes less than a minute.
Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.

Javascript is currently disabled in your web browser. For full site functionality, it is necessary to enable Javascript.
In order to enable it, please see these instructions.